The invention relates generally to printed circuit board assemblies and, in particular to, an apparatus and method for securing a printed circuit board and/or electrical components attached to the printed circuit board to a base plate without the use of screws or clips.
Printed circuit (PC) board assemblies are known. Such assemblies typically include a housing and a PC board populated with electrical components. The housing typically includes a base plate, side walls, and a cover. Depending on the circuitry attached to the PC board, the PC board may be secured to the base plate by clips, clamps, snap-fit mechanisms, glue, epoxy, solder, or screws. For example, PC boards that include circuitry with low power dissipation (e.g., PC boards that do not require attachment to a heat sink) are typically secured to the base plate or bottom of the housing using clips, snap-fit mechanisms, or other techniques that do not involve the use of screws. On the other hand, PC boards that include circuitry with high power dissipation (i.e., PC boards that require attachment to a base plate of a heat sink) are typically secured to the base plate with screws. In certain applications, some electrical components that are attached to the PC board must also be secured to the base plate for power dissipation purposes. For example, in power amplifier applications, the power transistors are typically secured to the heat sink with screws in order to insure sufficient heat transfer away from the transistor during operation. Failure to provide a high thermal conductivity path between the power transistor and the heat sink could result in transistor failure during operation.
Although screws are commonly used to attach PC boards and other electrical components to heat sink base plates in high power applications, the use of screws has many drawbacks. For example, screws require manual insertion and, therefore, are subject to human errors, such as omitted screws, stripped screw heads, and damaged electrical components due to slippage of the hand screw driver or electric torque driver off of the screw head. In addition, the use of screws requires tooling of each heat sink base plate to accommodate the screws. Thus, in most cases, each high power PC board design requires a unique heat sink base plate because PC board designs do not typically utilize the same base plate screw hole placements. Unique heat sink base plates add undesired costs to PC board assemblies.
Therefore, a need exists for an apparatus and method for securing a printed circuit board and/or electrical components attached to the printed circuit board to a base plate that may be used in high power dissipation applications and do not require the use of screws.